Esophageal Motor Disorders

GENERAL PRINCIPLES

Definition

• Achalasia is the most significant motor disorder of the esophagus, characterized by incomplete LES relaxation with swallowing and lack of adequate peristaltic contractions of the esophageal body.^32,64

• Esophagogastric junction outflow obstruction is a heterogeneous condition that includes incomplete achalasia-like disorders and structural processes (e.g., strictures, tight fundoplication, obstructing hiatus hernia).³²

• Esophageal hypermotility disorders consist of diffuse esophageal spasm, characterized by premature, nonperistaltic contractions in the esophageal body, and hypercontractile disorder with exaggerated esophageal body contractions.³²

• Esophageal hypomotility disorders are characterized by ineffective, or absent esophageal peristalsis, and can be associated with reflux symptoms and/or increased reflux burden.

DIAGNOSIS

Clinical Presentation

• Dysphagia, regurgitation, chest pain, and weight loss are typical achalasia symptoms. Aspiration pneumonia can also occur.

• Diffuse esophageal spasm and other spastic disorders may have obstructive symptoms (dysphagia, regurgitation) but also perceptive symptoms (chest pain) from heightened esophageal sensitivity.

• LES hypomotility diminishes barrier function, and esophageal body hypomotility affects esophageal clearance of refluxed material, which can lead to prolonged reflux exposure and reflux complications.

Diagnostic Testing

• Esophageal HRM represents the gold standard for the diagnosis of esophageal motor disorders.³⁴ HRM features categorize achalasia into three subtypes that have symptomatic and therapeutic implications.³²

• Barium radiographs (timed upright barium swallow) may demonstrate a typical appearance of a dilated intrathoracic esophagus with impaired emptying, an air-fluid level, absence of gastric air bubble, and tapering of the distal esophagus with a bird's beak appearance in achalasia.

• Endoscopy may help exclude a stricture or neoplasia of the distal esophagus in presumed achalasia and spastic disorders. Hypomotility disorders may also manifest a dilated esophagus but with a gaping gastroesophageal junction and evidence of reflux disease.

TREATMENT

Medications

• Smooth muscle relaxants such as nitrates or calcium channel blockers administered immediately before meals may provide short-lived symptom relief in spastic disorders and achalasia, but symptom response is suboptimal and side effects can be limiting. Phosphodiesterase inhibitors may provide benefit in hypercontractile disorders but are contraindicated in coronary disease.

• Botulinum toxin injection at endoscopy can improve dysphagia for several weeks to months in achalasia and spastic disorders with incomplete LES relaxation.⁶⁴ This approach may be useful in elderly and frail patients who are poor surgical risks or as a bridge to more definitive therapy.

• Neuromodulators (e.g., low-dose tricyclic antidepressants [TCAs]) may improve perceptive symptoms (such as chest pain) associated with spastic motor disorders and achalasia.

• Antisecretory therapy with a PPI is recommended for reflux associated with esophageal hypomotility disorders. No specific promotility therapy exists. Antireflux surgery should be approached with caution in advanced hypomotility disorders.

Surgical Management

Disruption of the circular muscle of the LES using pneumatic dilation or surgical incision (Heller myotomy) can result in durable symptom relief in achalasia, with comparable symptom outcomes.⁶⁴ Gastroesophageal reflux can result, which can be treated with lifelong acid suppression or concurrent partial fundoplication during myotomy. Esophageal perforation occurs in 3%-5% of patients with pneumatic dilation. POEM is minimally invasive with similar short-term symptom improvement but incidence of reflux is higher compared with surgical myotomy.⁶⁴

Complications

• Complications of achalasia include aspiration pneumonia and weight loss.

• Achalasia is associated with a 0.15% risk of squamous cell cancer of the distal esophagus, a 33-fold higher risk relative to the non-achalasia population.